The present invention relates to a wedge and, more particularly, to a dental wedge used in dental restoration.
If a decayed portion of a tooth is located near its interproximal area, the tooth structure itself is usually insufficient to provide support to the filling material during the filling process. In order to retain the filling material in an excavated cavity, while the filling material hardens, a band is typically positioned about the tooth and secured tightly about the tooth so that the band forms an outer shell or matrix. In addition, it is often necessary to separate the adjacent teeth so that the filling material when hardened will provide adequate contact between the teeth to restore the teeth to their original state.
To separate teeth and, further, to hold the band in place, dentists often use a wedge typically formed from wood or plastic. The wedge is inserted in the interproximal area or space between the adjacent teeth at the gum line. When forced into the space, the wedge causes the teeth to separate and, further, seals the band against the tooth to thereby retain the filling material in the cavity and to prevent overhang of the filling material in the interproximal area.
Most commercially available wedges are tetrahedral in shape and tend to have relatively sharp edges, which can induce trauma to the gum tissue. Furthermore, some wedge designs have an abrupt cross sectional design where it starts out as a point and within a short distance it is at its maximum cross sectional area. Since wedges come in different sizes for different interproximal spaces the dentist has to pick out what size he/she thinks will work. When a dentist places a wedge in the interproximal space, which has an abrupt cross-sectional change, there is a likelihood that the wedge will back out. The reason for this is that when inserted between teeth, the wedge is subject to an equal but opposite force generated by the separated teeth. In some wedges, the sides of the wedges incorporate protuberances, such as ridges or ribs, such as disclosed in U.S. Pat. No. 3,815,243; U.S. Pat. No. 3,890,714; and U.S. Pat. No. 6,074,210, which are provided to reduce the backing out of the wedge from between the teeth. However, it has been found in some instances that these protuberances may leave the restored surface with an irregular surface, which may cause accumulation of plaque or food and, thus, lead to decay and periodontal problems.
In addition, the inserted distal end of a conventional wedge, which is pointed, can further induce damage to the gum tissue. Most wedges have an inherent design so that when placed or forced into the interproximal space they also have a tendency to shift horizontally or slightly downward due to the contact between the wedge and the teeth. This can induce bleeding, and if the wedge is forced thru the interproximal space (which it is normally), a pointed wedge could either be driven into or through the sulcus (the sulcus is the gum tissue that surrounds a tooth). This could result in the patient experiencing some discomfort, and could inhibit the dentist from performing a proper restoration.
Consequently, there is a need for an improved dental wedge, which permits placement of the wedge with minimal trauma to the gum tissue and, further, in a manner, which does not degrade the surface of the restoration when removed.